1. Field of the Invention
The present invention relates to investigation of vehicle glazing panels particularly to assess the condition or structural integrity of the subject glazing panel. The invention has particular, although not exclusive, application in assessing the degree of damage to a windscreen having a flaw such as a break, crack or pit, and/or the quality of repair effected to such breaks, cracks, or pits.
2. State of the Art
Repairs are sometimes effected to vehicle glazing panels as an alternative to replacement, depending upon the severity, location and nature of the crack or break. Typically, during the repair procedure, resin is introduced into the flaw crack or break and the resin subsequently cures. The resin is selected such that, when cured, the optical characteristics of the resin repair match as closely as possible the optical characteristics of the material of the glazing panel. Often the resin is applied under partial vacuum or negative pressure to facilitate de-gassing of the resin and the crack or break in certain circumstances problems can occur in effecting a repair of adequate quality.
Certain prior art techniques have been proposed for investigating glazing panel condition using light transmission or scattering. Exemplary prior art techniques are disclosed in, for example, DE-A-19716809 and DE-A-3640891. An improved technique has now been devised.